Power lawn mower



Feb. 14, 1961 E. T. LEWIS 2,971,314

POWER LAWN MOWER Original Filed Oct. 12, 1955 8 Sheets-Sheet 1 INVENTOR.EVA/v I LEW/s ,4 TTORNEKS.

E. T. LEWIS POWER LAWN MOWER Feb. 14, 1961 8 Sheets-Sheet 2 OriginalFiled 001;. 12, 1955 INVENTOR. EVA/v flew/.5

BY if r I M u :Z/ITTORNEYS Feb. 14, 1961 E. T. LEWIS POWER LAWN MOWER 8Sheets-Sheet 3 Original Filed 001:. 12, 1955 INVENTOR. EVAN 7T LEW/vsATTORNEYS.

Feb. 14, 1961 E. T. LEWIS 2,971,314

POWER LAWN MOWER Original Filed Oct. 12, 1955 8 Sheets-Sheet 4 L 3 o 0 wm \D L 2; w

I 9\ w w E o 0 IN V EN TOR. EVAN 7. Laws A TTORNEYS Feb. 14, 1961 E. T.LEWIS POWER LAWN MOWER Original Filed Oct. 12, 1955 8 Sheets-Sheet 5INVENTOR. EVA/v 7. law/s Feb. 14, 1961 E. T. LEWIS POWER LAWN MOWER aSheets-Sheet 6 Original Filed Oct. 12, 1955 ENG/ VE .b" RR- 0 MW 7 ME aVA A W MI M V Q2 5 L M4 4 2 w z 2 2 2 4 a 2 u 6 2 a n w 2 M 2 w 2 ll 2 Ga. 9 .m n

W l W I ATTORZEQ E- Feb. 14, 1961 E. T. LEWIS POWER LAWN MOWER 8Sheets-Sheet 8 Original Filed 001;. 12, 1955 .5 ms T/ YN mw R V: Mm W Tl A Aw M POWER LAWN MOWER Evan T. Lewis, Stroudsburg, Pa., assignor toWorthington Mower Company, Stroiulsburg, Pa., a corporation of DelawareOriginal application Oct. 12, 1955, Ser. No. 540,063,

now Patent No. 2,909,882, dated Oct. 27, 1959. Divided and thisapplication Apr. 30, 1959, Ser. No.

2 Claims. (Cl. 5626) The application relates to power lawn mowers andmore particularly to power lawn mowers having a mowing unit located infront of the mower and additional mowing units disposed at the sides.

This application is a division of and was copending with applicationSerial No. 540,063, which was filed on October 12, 1955 and was issuedas Patent No. 2,909,882 on October 27, 1959 for an invention entitledReel-Type Gang Mower. Portions of the written description below and thematters illustrated in the drawings of the present application are notclaimed herein but are claimed in said Patent No. 2,909,882.

Power mowers used for cutting grass on golf courses, parks, cemeteries,athletic fields and other large areas, must overcome many difiicultiesto give a satisfactory cut. The mower must be able to achieve propercutting of the grass even though the terrain is very irregular, that is,the mower must cut equally well on rough, hilly terrain as on large,flat areas. In addition, the cut should be satisfactory whether thegrass be either short or long, coarse or fine. With regard to thislatter matter the clip frequency of the mower is a very importantfactor. Clip frequency is a term denoting the relationship of the speedof the cutting mean to the forward speed of the mower. The greater thespeed of the cutting means the finer will be the cut and the slower thecutting speed the rougher will be the cut.

In striving to achieve a mower which will satisfactorily overcome theaforementioned problems many various structures have heretofore beentried. One of the most satisfactory designs has utilized individualmowing units positioned both in front of the mower and at either side.This arrangement has the advantage of placing the mowing units inpositions where they may be easily seen by theoperator thereby enablinghim to achieve a better control of the cutting operation. It alsoresults in a better cut because it avoids streaks caused by the crushingof the grass by the tractor wheels before the mowing units pass. overit..

Such an arrangement, however, presents serious problems in achievinggood terrain-following qualities because of the difficulty in adequatelysupponting the mowing units to withstand rugged use while, at the sametime, achieving flexibility required by irregular ground. Heretofore,prior known mower constructions have not been completely satisfactory inthis regard. Specifically, it has been diflicult to obtain a supportingstructure for the ront mowing units which will permit a sufficientdegree of rocking movement about both a longitudinal and transverse axisof the machine. A further difliculty has been in developing a completelysatisfactory method of supporting the side units so as to givesubstantially even support throughout their length. Another difiicultyhas been the necessity for providing various take-up devices for thechain drives due to the variations in the length of the transmissionsystems for the various positions of the mowing units.

Another important difficulty has to do with clip he ice quency.Heretofore it has been customary to take off the power for the mowingunits at a point located after the transmission for the tractor wheels.This results in a constant clip frequency between the cutting speed ofthe mowing units and the forward speed of the tractor for each time themower is shifted into a different gear the speed of the mowing units iscorrespondingly changed. Accordingly, such a mower has but one degree ofcutting ability, which is built into the machine at the time the gearsystem for the mower is designed. In order to achieve acceptable resultsfor many different grass conditions this choice has to be a compromise.

In the applicants present invention these difliculties are overcome.Applicant has achieved a construction in which the front mowing unit isprovided with a rugged supporting means that permits a wide degree ofrocking motion about both a longitudinal and transverse axis of themower. Coupled with an ability to swing up and down, applicants frontmowing unit achieves excellent terrain-following qualities.Additionally, the side mowing units are supported in a manner to give afloating action, that is, with substantially even distribution of theweight along the length of the mowing units and provision is madewhereby the length of the power drive system is constant whether theunits are in a cutting or retracted position.

Furthermore applicants mower construction permits variations in theforward speed of the mower without altering the speed of the mowingunits, thereby achieving variations in the clip frequency. Thusapplicants mower may be controlled to give the proper clip frequency forwhatever grass condition is being encountered. For example, it i nowpossible, with the applicants invention, to produce a power mower whichwill be able to give a completely satisfactory cut on the relativelylong grass of a golf course rough, the shorter grass of the fairways andthe still shorter grass bordering the greens.

Briefly and generally, the applicants invention comprises a frameprovided with a plurality of wheels so as to be movable. Disposed infront of the frame and attached thereto is a front mowing unit andsimilar mowing units are disposed at the sides of the frame. A gasolineengine, or any other suitable power source, is mounted on the frame andsupplies power for the mowing units and. for the wheels of the frame.Power transmission means are provided between the engine and the mowingunits and the engine and the wheels and are arranged so that the speedof the wheels may be varied without varying the speed of the mowingunits. Preferably this is achieved by locating the power take-off pointfor the mowing units ahead of the speed changing means for the tractionwheels so as to permit varying speed ratios between the engine and thetraction wheels but only a constant speed ratio between the engine andthe mowing units.

In general arrangement the engine is preferably mounted on the frame atthe front so as to provide room on the remainder of the frame for a seatand platform to support the operator and for suitable steering apparatusby which the mower may be guided. The traction wheels for the mower arelocated at the forward or front part of the frame so as to support theweight of the engine and the various transmission means while a steeringwheel, or wheels, is positioned at the rearward end of the frame andpivotally joined thereto. Suitable mechanical linkages connect thelatter wheels with the steering apparatus.

The means for attaching the front mowing unit to the frame generallycomprises a yoke-like member pivotally connected to the frame,preferably at the axles for the front wheels, so as to be swingable upand down'with respect to the ground. Provision is made for substantialrocking movement of the unit about a longitudinal axis of the mower sothat the mowing unit may readily adapt itself to mowing on the side of ahill. T this end the front mowing unit is preferably provided with arelatively short, but rugged, cylindrical shaft forming an extension onthe central portion thereof which is journalled within a correspondinglyshaped bushing or hearing secured to the center of the yoke-like memberon the frame.

Each of the side mowing units is supported so as to distribute itsweight evenly, along its length by joining the unit to the frame with adouble pivoted link memher, that is, a link member which is pivotallyconnected to both the frame and the mowing unit. This arrangementpermits the side units to assume an angle for proper cutting of thegrass regardless of the position of the frame. Thus, the mower may cuttwo flat surfaces of different levels while the mower travels along theinclined surface between them. Additionally, each link member isprovided with spring means connected to the link and the frame so as toconstantly urge the link in an upward direction, thereby avoidinggouging of the ground by the mower at the pivot point between the linkand the mowing unit. Preferably the spring means are disposedlongitudinally along the frame so as to be out of the way ofthe'operator and are joined to flexible connectors secured to the linkmembers, said connectors passing over movable direction changingdevices. Further protection against gouging of the turf at the criticalpoint of pivot between each side mowing unit and its link memher isachieved by substantially increasing the length of the rollers for themowing units so that they extend inwardly toward the mower past theinner end of the mowing unit to a point adjacent the pivot point betweenthe link and the mowing unit.

For the purpose of obtaining freedom of movement for the side mowingunits coupled with a constant length of their power drive applicantprovides a transmission system for each unit in which the centers ofrotation for the transmission means coincide with the pivot centers ofthe mowing units and the link members. In the preferred form of theinvention a drive shaft is provided on the frame and positioned so thatits center coincides with the center of the pivotal connection betweenthe frame and a link member. Each mowing unit is provided with a pair ofoppositely disposed extensions that are journalled in the outer end ofthe link member to form the pivotal connection between the frame andlink. A rotary shaft is also provided on the mowing unit and positionedso that its center coincides with the center of the extensions. Bot-hthis shaft and the drive shaft may advantageously be disposedlongitudinally of the frame and the main shaft of the cutting means forthe mowing units may be positioned transversely to the frame. Suitablegear elements, or other power transmission means,

. are provided between the rotary shaft and the main shaft and therotary shaft and the drive shaft, whereby the power of the engine may betransmitted to the mowing units.

It will be understood that the foregoing general description and thefollowing detailed description as well are exemplary and explanatory ofthe invention but are not restrictive thereof.

Of the drawings:

Fig. 1 is a side elevation of a power mower constructed in accordancewith the preferred form of the invention;

Fig. 2 is a top plan view partly :broken away and in section with theupper portion of the mower taken away showing the arrangement of themowing units and traction and steering wheels;

Fig. 3 is an enlarged top sectional view showing the pivotal connectionsbetween a side mowing unit and the frame and the transmission meanstherefor;

F g- 4 is an nl g d re r iew with parts broken away and in section of aside mowing unit showing the supporting structure therefor;

Fig. 5 is a side view partly in section taken along the line 5-5 in Fig.4, looking in the direction of the arrows;

Fig. 6 is an enlarged rear view with parts broken away and in section ofa side unit in a raised position;

Fig. 7 is a view, partly in section, taken along the line 77 in Fig. 4looking in the direction of the arrows;

Fig. 8 is a schematic view showing the various transmission systems forthe mowing units and the traction wheels;

Fig. 9 is an enlarged vertical sectional view through the center line ofthe clutch for the traction wheels;

Fig. 10 is a similar view showing the arrangement of elements on theshaft of the transmission for the traction wheels and mowing units; 7

Fig. 11 is a horizontal sectional view through the main clutch for themowing units; and

Fig. 12 is a sectional view taken along the line 12-12 in Fig. 11looking in the direction of the. arrows.

Referring now to the drawings and at first to Fig. 1 there is shown apower mower constructed in accordance with the teachings of theapplicants invention. The mower generally comprism'a frame 10 having aplurality of traction wheels 12 secured thereto to propel the mower overthe turf being cut and steering wheels 14- at the rearward end portionof the frame by which the mower may be guided. At its forward end theframe 1 supports an engine 16 which furnishes the power for the mower,and suitable power transmission means are provided whereby the power ofthe engine is transmitted to the mowing unitsand the traction wheels. Inthe form of the invention shown in the drawings the mower is providedwith one front mowing unit 18 and two side mowing units 20, 21, eachside unit being disposed to one side of the frame 10. A platform 22 anda seat 24 are provided on the mower to'support an operator, the platformbeing secured to the frame 10 and the seat resiliently mounted to thesteering wheel chassis 26. Chassis 26 is pivotally secured to the frame10 by the yoke 28 which is jo-urnalled to a stud shaft 30 in the boss32. The upper portion 34 of the yoke 28 carries a sprocket wheel 36 thatis connected by an endless chain 38 to a pulley and sprocket wheel 40rotatably mounted on another stud shaft 42 within the platform 22. Achain 44 connects the pulley and sprocket wheel 40 to a sprocket wheel(not shown) on the steering column 48. A steering wheel 50 on the column48 enables the operator to control the direction of the mower travel bymaneuvering the position of the steering chassis 26 with respect to theframe 19.

Adjacent the front of the mower the frame It) takes the form of twoparallel longitudinal beams 52 (Fig. 2) to which are secured thesupports 54 for the axle 56 of the traction wheels 12. Pivotally securedto the ends of the axle 56 is a yoke-likemem'oer 58, provided at itscentral portion with a heavy bearing 60. 'It is to this yoke 58 that thefront mowing unit 18 is attached and to this end the mowing unit isprovided with a cylindrical extension 62 adapted to be rotatablyreceived within the bearing 66 as to enable the mowing unit 18 to rockabout both a longitudinal and transverse axis of the mower. A pair ofguide members in the form of runners 64 are secured to the yoke 58adjacent the ends of the mowing unit 18 and act as support plates forthe rollers 66 to give the unit support against shock during itsterrainfollowing motions. As shown in the drawing, Figure 2, the rollers66 are mounted at the ends of the front mowing unit 18 and the runners64 are located on the yoke 58 in registry with the rollers 66. The guidemembers 64 do not ordinarily contact the roller 66.

In the mowing units shown in the drawings for purposes of illustration,the cutting means are of the common reel type in which a plurality ofspirally-shaped blades Qt} Fig; 7) are fixedly mounted in circularsupport plates, or rings 70 so as to form a generally cylindricalassembly. The plates 70 are fixed to a rotary shaft 72 journalled forrotation in the end plates 74 joined together by the end plate supportmembers 76. A bed knife 78, having a cutting edge 80, is secured between the end plates 74 by means of the angle bar 82. Mounted behind theblades and in contact with the turf is a roller 84 having each endportion rot atably fastened to a bracket 86 on the end of a threaded rod88 that depends from the end plate 74. Adjustment of the height of thecut by the reel is controlled by a nut 90 threaded onto the rod 88 onthe top side of the lug 92 in the end plate 74 by which the roll-er maybe lowered or raised with respect to the bed knife 78. A cover, or grassshield, 95 is secured to the top of the unit to prevent the cut grassfrom being flung upwardly into the operators face.

The side mowing units 20, 21 are each connected to the frame by means oflink members 94. To this end the inner end plate 74 of each unit isprovided with an extension 96 which is bolted to the plate 74 by thestuds 98. Preferably the extension takes the form of a hollow casinghaving a generally cylindrical hub 100 with oppositely disposed studshafts 102 extending from either side of the hub, which shafts act aspivot points for the link member 94. Accordingly, each link member 94 isprovided with a pair of spaced bushing housings 104 at the outer endportions thereof to pivotally receive the stud shafts 102 on extension96. The inner end portions of the link members 94 are also provided withbushing housings 106 adapted to be pivotally mounted on a longitudinallydisposed hollow rod 108 fixedly positioned in a'bracket 110 suspendedfrom the frame 10. Thus each side mowing unit is attached to the framethrough a double pivot which permits the unit to accommodate itself tothe level of the turf with respect to the mower frame and also to theparticular inclination of the turf.

To obtain a relatively uniform weight distribution over the length ofthe side mowing units and especially to avoid exerting a downward forceat the point of pivot between the unit and the link, each link 94 isprovided with a resilient support constantly urging it in an upwarddirection. A small bracket 112 is fixed to the upper face 114 of eachlink. To the bracket 112 is fastened a chain 116 which passes over asprocket wheel 1 18 on a stud shaft 120 fixed in the frame 10. Theopposite, or free, end of the chain 116 is fastened to a spring 122preferably disposed longitudinally next to the frame 10 and secured to athreaded stud 124 in a lug 126. Adjustment of the tension of the springis effected by varying the position of the stud 124 on the lug 126 bymeans of the nut 128.

Further support for the side mowing units adjacent the critical pivotpoint between the unit and its connecting link member is provided byapplicants roller construction in which the inner bracket 86$ for theroller 848 is formed in the shape of an exaggerated goose neck and thelength of the roller is made greater than normal so as to extendinwardly toward the mower past the end of the blades 68 to a pointadjacent the critical pivot point and beyond the inner end plate 74 (seeFigures 2, 4 and 6). Any tendency of the side unit to dig into the turfat this pivot point is effectively resisted by the pressure of thisincreased portion of the roller against the ground.

However, it should be understood that the roller construction for thefront mowing unit (see Figure 2) does not embody these structuralfeatures. Unlike the side units, the inner bracket 86 of the frontmowing unit is not formed in the shape of an exaggerated goose neck; andfurther unlike the side units, the roller 84 of the .front unit is onlyslightly longer than the blades 68 and is positioned within the endplates 74.

The side mowing units 20, 21 are adapted to fold upwardly out of the waywhenever it is desired to travel without cutting (Fig. 6). Accordingly,the outer end 6 plate 74 of each unit is provided with a handle 13% bywhich the operator may swing the units. Suitable holding means areprovided to hold the units in their retracted positions and the steeringcolumn 48 carries a pair of hook arms 132, the end portions: of whichare adapted to engage openings in the lugs 134- mounted on the top frontstiffening bar 76. In order to prevent the inner end of the mowing unitsfrom coming too close to the ground when in the retracted position a lug136 is provided on the inner end of the hub 10!) of exten- "sion 96 anda chain 138 is attached to the lug. The opposite end of the chain 138 ispassed between a catch fashioned by two parallel fingers 142 secured tothe stud shaft fixed at the frame 10. As the length of the chain 138 isquite short the side mowing unit is prevented from gouging into the turfdue to jackknifing at the critical pivot point. When the units are intheir cutting positions the hook arms 132 are held out of the operatorsway by the clamps 144 fastened to the steering column 48.

Referring now to Figs. 8-12 for a description of the various powertransmission means there is shown (in phantom) a schematicrepresentation of an engine 16. The engine shaft 146 extends outwardlyfrom the engine casing and has mounted on and keyed to its outer portiona hollow sleeve 148. Keyed to the inner end of the sleeve 148 is asprocket wheel 15'!) so that rotation of the engine shaft 146 and sleeve148 causes the sprocket wheel to rotate also. Sprocket wheel 150 isconnected by an endless chain 152 to a double sprocket wheel 154 mountedadjacent the speed changer, or gear box, 158. The double sprocket wheel154 is mounted for free rotation on the hub in which the shaft 156 forthe speed changer is rotatably journalled. From the double sprocketwheel 154 power is transmitted to another sprocket wheel 162 immediatelyadjacent the clutch 164 for all three of the mowing units by an endlesschain 163.

Clutch 164 (Fig. -11) generally comprises a large diameter disc 165having a flange 166 about the periphery thereof, to which is bolted tworing elements. The inner surface of these ring elements is provided withgear teeth 168 to form an internal gear hereinafter referred to as theflange 166. Disc 165 is also provided with an extensive hub portion 170upon which the sprocket wheel 162 is freely mounted. Immediatelyadjacent the wheel 162 are a pair of friction discs 172, 173, one oneach side, and secured to the hub 170 so as to rotate therewith. Onedisc 172 is held by a lock ring 174 and the other disc 173 is constantlyurged toward the wheel by a spring 176 interposed between the disc 173and an adjusting disc 178. The purpose of this construction is toprotect the reels and power driving means against injury in case any ofthe mower units should become jammed by a tree branch or the like.Adjustment of the spring tension is effected by the ring 180 threaded onthe hub- 170.

A thick-walled sleeve 182 is fixed to the power shaft 184 for the mowingunits and carries three clutch discs 186 keyed thereto. Interposedbetween the clutch discs 186 are a plurality of gear shaped rings 188which form external gears having teeth 190 corresponding to the teeth168 of the internal gear on the inner surface of the flange 166 andwhich constantly rotates with the flange. When the clutch discs 186 arepressed into firm contact with the rings 188 the discs 186 and thesleeve 182 also rotate, thereby driving the shaft 184. This pressingcontact is effected by means of a clutch lever 192 pivotally connectedto the frame 10 at 194. Lever 192 is formed with a circular section 196having an inner ring 198 mounted therein. The inner ring 198 bearsagainst the ends of three equally spaced cam levers 200, the oppositeends of which are provided with cam faces 201 that bear against theoutermost clutch disc 186. An

adjustable retaining ring 202 on the sleeve 182 furnishes a pivot pointfor the cam levers 200. Movement of lever .192 outwardly to the rightcauses the cam levers 200 to press the clutch discs 186 into contactwith the rings 188 while movement to the left releases the discs 186from the rings 188.

A sprocket wheel 204 is keyed to the end of the shaft 184 and isconnected by a double sprocket wheel 208 on the wheel axle 56 by anendless chain 206. Double sprocket wheel 208 is, in turn, connected to asprocket Whe l 212 on the rotary shaft 72 of the front mowing unit by anendless chain 214. At its opposite end shaft 184 is provided with abeveled gear 216 that meshes with a similar gear 218 on a longitudinalshaft 220. A dog clutch 222, actuated by lever 224, is slidably keyed tothe shaft 220 so as to be engageable with a sprocket wheel 226 freelymounted thereon. Sprocket wheel 226 is connected by an endless chain 228to a sprocket wheel 230 on a longitudinal shaft 232 mounted in thebracket 110 suspended-from the frame 10.

Referring now to Fig. 3 shaft 232 is rotatably mounted within the hollowrod 108 and carries a double sprocket wheel 234 at an end opposite tothat of the wheel 230. An endless chain 236 for each sprocket of wheel23'4 connects the wheel with a similar sprocket wheel 238 keyed to theend of a short shaft 240 rotatably mounted within the hollow casing ofthe hub 100 of the extension 96 and the stud shafts 102. The short shaft240 on the left hand side of the machine as shown on Figure 3 isslightly longer than the corresponding short shaft 240R provided on theright hand side of the machine (see Figure 8). Thus the centers of thesprocket wheels exactly coincide with the centers of the pivot pointsfor each link member 94. A bevel gear 242 mounted on the inner end ofshaft 240 within the hub 100 meshes with a similar gear 244 on atransverse shaft 246. Shaft 246 is connected to the rotary shaft 72 ofthe cutting means by an internally splined sleeve 248. This arrangementof the transmission means permits pivotal movement of the mowing unitand connecting link member without changing the length of the system andwithout requiring any take-up devices for the endless chains. It willalso be observed that if the clutches 164 and 222 are engaged the speedof the reels for the mowing units will be directly proportional to thespeed of the engine.

The power take-off from the engine shaft 146 for the traction wheels 12occurs at a point after the sprocket wheel 150. A clutch 250, similar tothe clutch 164, is provided on the outer portion of the hollow sleeve148. A disc 252 is keyed to the sleeve 148 on the engine shaft 146 andis provided with an integral clutch disc 254 and also with a movableclutch disc portion 256, the two discs being constantly urged apart bysprings 258 only one of which is shown. The movable disc 256 is pressedinto pressing contact with the clutch rings 260 by means of the rollerarms 262 which carry rollers 266, 268 for engagement with a hardenedring 257 on the clutch disc 256 and a slidable cam member 270respectively. Cam member 270 is mounted on a slide 272 actuated by theclutch lever 274. As the roller arms 262 are pivotally mounted on theadjusting ring 276 movement of the slide 272 toward the right (as shownin Fig. 9) will permit the disc 256 to be moved away from the rings 260.Movement to the left moves the disc 256 into contact with the rings.

Clutch 250 is also provided with a large diameter disc 278 having aflange 280 to which is bolted a ring element bearing internal gear teeth282. On the hub 284 of the 8 clutch, a sprocket wheel 286 is keyed forrotation therewith while the hub is rotatably mounted on the bushing288. Sprocket 286 is connected by an endless chain 290 'to a sprocketwheel 292 keyed to the shaft 156 of the gear box, or transmission 158. Ashift lever 294 is provided for changing gears in the speed changer tovary the speed ratios between the engine shaft 146 and the tractionwheels 12. A sprocket wheel 296, on the power output side of thetransmission is connected by chain 298 to a sprocket wheel 300 on thewheel axle 56. Thus, it will be understood, a driving connection isprovided from the engine power source through the speed changer to thetraction wheels and a separate driving connection is provided from theengine power source to the mowing units. It will be noted that as thetransmission or speed changer for the traction wheels is arranged afterthe power take-off for the mower units (the driving connections areseparate) the speed ratio of the traction wheels with respect to enginespeed may be varied without changing the speed ratio between the mowingunits and the engine speed. The clip frequency of the mower cantherefore be easily changed simply by changing the gears in the tractionwheel transmission.

The invention in its broader aspects is not limited to the specificmechanisms shown and described but departures may be made therefromwithin the scope of the accompanying claims without departing from theprinciples of the invention and without sacrificing its chiefadvantages.

What I claim is:

1. A power mower comprising a frame, an axle connected to the front ofthe frame and extending transversely thereof, a wheel rotatably mountedat each end of the axle to support and transport the front of the frame,at least one wheel rotatably mounted on the rear of the frame to supportand transport the frame in conjunction with the first mentioned wheels,a power source mounted on the frame, a driving connection between thepower source and at least one of the wheels to drive the wheel and movethe frame, a mowing unit having cutting means, and means for attachingthe mowing unit to the front of the frame, said attaching meanscomprising a yokemember pivotally mounted on said axle and extendingforwardly of the frame to pivot about a substantially horizontal axis,and said attaching means also comprising a connecting member rotatablyconnecting the mowing unit and the center of the yoke, said connectingmember being rotatable about a longitudinal axis of the frame.

2. The subject matter of claim 1 characterized by the fact that saidconnecting member is provided with a longitudinal extension, the yoke isprovided with a bearing adapted to rotatably receive the longitudinalextension, said mowing unit has two end portions at opposite endsthereof, a roller is mounted on each end portion of the mowing unit, andthe yoke has a pair of guide member runners secured to and located onthe yoke in registry with said rollers to engage the rollers and toprovide a track for each roller whereby guided and supported up and downmovement of the mowing unit over irregular terrain is facilitated.

References Cited in the file of this patent UNITED STATES PATENTS2,509,993 Soss May 30, 1950 2,696,705 Greber Dec. 14, 1954 2,750,726Boucard et a] June 19, 1956

